Combining LC-MS/MS and hollow-fiber infection model for real-time quantitation of ampicillin to antimicrobial resistance.

Although a marked decrease in mortality associated with bacterial infections is attributed to the discovery of antibiotics, antibiotic resistance has become a global health concern due to their misuse. A dynamic in vitro hollow-fiber system was used to study antibiotic resistance in Escherichia coli using ampicillin. An LC-MS/MS assay was validated for quantitative analysis of ampicillin in Luria-Bertani broth. The assay was linear from 0.10-50.00 μg/ml. The assay met acceptance criteria for inter- and intra-assay precisions and accuracies across three quality controls. Stability of ampicillin was confirmed at three different storage conditions. In vitro data were similar to simulated plasma PK data further confirming the appropriateness of the experimental design to quantify antibiotics and study occurrence of antimicrobial resistance in real-time.